Have

Psychic Corrosion

Whenever you draw a card, each opponent mills two cards.

Anchor to the Aether

Put target creature on top of its owner's library. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Endless Evil

Enchant creature you control
At the beginning of your upkeep, create a token that's a copy of enchanted creature, except the token is 1/1.
When enchanted creature dies, if that creature was a Horror, return Endless Evil to its owner's hand.

Hell's Caretaker

{T}, Sacrifice a creature: Return target creature card from your graveyard to the battlefield. Activate only during your upkeep.

Memory Plunder

You may cast target instant or sorcery card from an opponent's graveyard without paying its mana cost.

Unclaimed Territory

As Unclaimed Territory enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

Captain N'ghathrod

Horrors you control have menace.
Whenever a Horror you control deals combat damage to a player, that player mills that many cards.
At the beginning of your end step, choose target artifact or creature card in an opponent's graveyard that was put there from their library this turn. Put it onto the battlefield under your control.

Mindcrank

Whenever an opponent loses life, that player mills that many cards. (Damage causes loss of life.)

Path of Ancestry

Path of Ancestry enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Brainstealer Dragon

Flying
At the beginning of your end step, exile the top card of each opponent's library. You may play those cards for as long as they remain exiled. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.
Whenever a nonland permanent an opponent owns enters the battlefield under your control, they lose life equal to its mana value.

Bitter Ordeal

Search target player's library for a card and exile it. Then that player shuffles.
Gravestorm (When you cast this spell, copy it for each permanent put into a graveyard this turn. You may choose new targets for the copies.)

Rise of the Dark Realms

Put all creature cards from all graveyards onto the battlefield under your control.

Gyruda, Doom of Depths

Companion — Your starting deck contains only cards with even mana values. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
When Gyruda enters, each player mills four cards. Put a creature card with an even mana value from among the milled cards onto the battlefield under your control.

Lazav, Dimir Mastermind

Hexproof
Whenever a creature card is put into an opponent's graveyard from anywhere, you may have Lazav, Dimir Mastermind become a copy of that card, except its name is Lazav, Dimir Mastermind, it's legendary in addition to its other types, and it has hexproof and this ability.

Herald's Horn

As Herald's Horn enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Zellix, Sanity Flayer

Hive Mind — Whenever a player mills one or more creature cards, you create a 1/1 black Horror creature token.
{1}, {T}: Target player mills three cards.
Choose a Background (You can have a Background as a second commander.)

Wharf Infiltrator

Skulk (This creature can't be blocked by creatures with greater power.)
Whenever Wharf Infiltrator deals combat damage to a player, you may draw a card. If you do, discard a card.
Whenever you discard a creature card, you may pay {2}. If you do, create a 3/2 colorless Eldrazi Horror creature token.

Dread Slaver

Whenever a creature dealt damage by Dread Slaver this turn dies, return it to the battlefield under your control. That creature is a black Zombie in addition to its other colors and types.

Cut Your Losses

Casualty 2 (As you cast this spell, you may sacrifice a creature with power 2 or greater. When you do, copy this spell and you may choose a new target for the copy.)
Target player mills half their library, rounded down.

Hypnox

Flying
When Hypnox enters, if you cast it from your hand, exile all cards from target opponent's hand.
When Hypnox leaves the battlefield, return the exiled cards to their owner's hand.

Fleshwrither

Transfigure {1}{B}{B} ({1}{B}{B}, Sacrifice this creature: Search your library for a creature card with the same mana value as this creature, put that card onto the battlefield, then shuffle. Transfigure only as a sorcery.)

Umbris, Fear Manifest

Umbris, Fear Manifest gets +1/+1 for each card your opponents own in exile.
Whenever Umbris or another Nightmare or Horror you control enters, target opponent exiles cards from the top of their library until they exile a land card.

Lullmage's Domination

This spell costs {3} less to cast if it targets a creature whose controller has eight or more cards in their graveyard.
Gain control of target creature with mana value X.

Spoils of Evil

For each artifact or creature card in target opponent's graveyard, add {C} and you gain 1 life.

Crown of Ascension

Enchant creature
Enchanted creature has flying.
Sacrifice Crown of Ascension: Enchanted creature and other creatures that share a creature type with it gain flying until end of turn.

Realmbreaker, the Invasion Tree

{2}, {T}: Target opponent mills three cards. Put a land card from their graveyard onto the battlefield tapped under your control. It gains "If this land would leave the battlefield, exile it instead of putting it anywhere else."
{10}, {T}, Sacrifice Realmbreaker, the Invasion Tree: Search your library for any number of Praetor cards, put them onto the battlefield, then shuffle.

Teferi's Tutelage

When Teferi's Tutelage enters, draw a card, then discard a card.
Whenever you draw a card, target opponent mills two cards. (They put the top two cards of their library into their graveyard.)

Dauthi Horror

Shadow (This creature can block or be blocked by only creatures with shadow.)
Dauthi Horror can't be blocked by white creatures.

Phyrexian Obliterator

Trample
Whenever a source deals damage to Phyrexian Obliterator, that source's controller sacrifices that many permanents of their choice.

Don't Have

Skulking Fugitive

When Skulking Fugitive becomes the target of a spell or ability, sacrifice it.

Ingenious Skaab

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
{U}: Ingenious Skaab gets +1/-1 until end of turn.

Traumatize

Target player mills half their library, rounded down.

Maddening Cacophony

Kicker {3}{U}
Each opponent mills eight cards. If this spell was kicked, instead each opponent mills half their library, rounded up.

Mind Flayer

Dominate Monster — When Mind Flayer enters, gain control of target creature for as long as you control Mind Flayer.

Frightcrawler

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Threshold — As long as seven or more cards are in your graveyard, Frightcrawler gets +2/+2 and can't block.

Ashiok, Dream Render

Spells and abilities your opponents control can't cause their controller to search their library.
−1: Target player mills four cards. Then exile each opponent's graveyard.

Memory Erosion

Whenever an opponent casts a spell, that player mills two cards.

Imperious Mindbreaker

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Imperious Mindbreaker is paired with another creature, each of those creatures has "Whenever this creature attacks, each opponent mills cards equal to its toughness."

Grazilaxx, Illithid Scholar

Whenever a creature you control becomes blocked, you may return it to its owner's hand.
Whenever one or more creatures you control deal combat damage to a player, draw a card.

Grell Philosopher

Aberrant Tinkering — When Grell Philosopher enters and at the beginning of your upkeep, each Horror you control gains all activated abilities of target artifact an opponent controls until end of turn. You may spend blue mana as though it were mana of any color to activate those abilities.

Ashen Powder

Put target creature card from an opponent's graveyard onto the battlefield under your control.

Dreadwurm

Landfall — Whenever a land you control enters, Dreadwurm gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Mindshrieker

Flying
{2}: Target player mills a card. Mindshrieker gets +X/+X until end of turn, where X is the milled card's mana value.

Revealing Eye

Menace
When this creature transforms into Revealing Eye, target opponent reveals their hand. You may choose a nonland card from it. If you do, that player discards that card, then draws a card.

Concealing Curtains

Defender
{2}{B}: Transform Concealing Curtains. Activate only as a sorcery.

Concealing Curtains // Revealing Eye

Krydle of Baldur's Gate

Whenever Krydle of Baldur's Gate deals combat damage to a player, that player loses 1 life and mills a card, then you gain 1 life and scry 1.
Whenever you attack, you may pay {2}. If you do, target creature can't be blocked this turn.

Dauthi Embrace

{B}{B}: Target creature gains shadow until end of turn. (It can block or be blocked by only creatures with shadow.)

Overcharged Amalgam

Flash
Flying
Exploit (When this creature enters, you may sacrifice a creature.)
When Overcharged Amalgam exploits a creature, counter target spell, activated ability, or triggered ability.

Call to the Kindred

Enchant creature
At the beginning of your upkeep, you may look at the top five cards of your library. If you do, you may put a creature card that shares a creature type with enchanted creature from among them onto the battlefield, then you put the rest of those cards on the bottom of your library in any order.

Gurgling Anointer

Flying
Whenever you draw your second card each turn, put a +1/+1 counter on Gurgling Anointer.
When Gurgling Anointer dies, return another target creature card with mana value less than or equal to Gurgling Anointer's power from your graveyard to the battlefield.

Honored Heirloom

{T}: Add one mana of any color.
{2}, {T}: Exile target card from a graveyard.

Ashiok, Nightmare Muse

+1: Create a 2/3 blue and black Nightmare creature token with "Whenever this creature attacks or blocks, each opponent exiles the top two cards of their library."
−3: Return target nonland permanent to its owner's hand, then that player exiles a card from their hand.
−7: You may cast up to three spells from among face-up cards your opponents own from exile without paying their mana costs.

Fractured Sanity

Each opponent mills fourteen cards.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)
When you cycle Fractured Sanity, each opponent mills four cards.

Stonespeaker Crystal

{T}: Add {C}{C}.
{2}, {T}, Sacrifice Stonespeaker Crystal: Exile any number of target players' graveyards. Draw a card.

Faceless Devourer

Shadow (This creature can block or be blocked by only creatures with shadow.)
When Faceless Devourer enters, exile another target creature with shadow.
When Faceless Devourer leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Necrogen Scudder

Flying
When Necrogen Scudder enters, you lose 3 life.

Nautiloid Ship

Flying
When Nautiloid Ship enters, exile target player's graveyard.
Whenever Nautiloid Ship deals combat damage to a player, you may put a creature card exiled with Nautiloid Ship onto the battlefield under your control.
Crew 3

Hedonist's Trove

When Hedonist's Trove enters, exile target opponent's graveyard.
You may play lands from among cards exiled with Hedonist's Trove.
You may cast spells from among cards exiled with Hedonist's Trove. You can't cast more than one spell this way each turn.

Phyrexian Revoker

As Phyrexian Revoker enters, choose a nonland card name.
Activated abilities of sources with the chosen name can't be activated.

Duskmantle, House of Shadow

{T}: Add {C}.
{U}{B}, {T}: Target player mills a card.

Keening Stone

{5}, {T}: Target player mills X cards, where X is the number of cards in that player's graveyard.

Tormod's Crypt

{T}, Sacrifice Tormod's Crypt: Exile target player's graveyard.

Drown in Dreams

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Target player draws X cards.
• Target player mills twice X cards.

Sentinel Totem

When Sentinel Totem enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}, Exile Sentinel Totem: Exile all graveyards.

Polymorphous Rush

Strive — This spell costs {1}{U} more to cast for each target beyond the first.
Choose a creature on the battlefield. Any number of target creatures you control each become a copy of that creature until end of turn.

Bloodchief Ascension

At the beginning of each end step, if an opponent lost 2 or more life this turn, you may put a quest counter on Bloodchief Ascension. (Damage causes loss of life.)
Whenever a card is put into an opponent's graveyard from anywhere, if Bloodchief Ascension has three or more quest counters on it, you may have that player lose 2 life. If you do, you gain 2 life.

Court of Cunning

When Court of Cunning enters, you become the monarch.
At the beginning of your upkeep, any number of target players each mill two cards. If you're the monarch, each of those players mills ten cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Breach the Multiverse

Each player mills ten cards. For each player, choose a creature or planeswalker card in that player's graveyard. Put those cards onto the battlefield under your control. Then each creature you control becomes a Phyrexian in addition to its other types.

Geth, Lord of the Vault

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
{X}{B}: Put target artifact or creature card with mana value X from an opponent's graveyard onto the battlefield under your control tapped. Then that player mills X cards.

Synchronized Eviction

This spell costs {2} less to cast if you control at least two creatures that share a creature type.
Put target nonland permanent into its owner's library second from the top.

Avatar of Woe

If there are ten or more creature cards total in all graveyards, this spell costs {6} less to cast.
Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
{T}: Destroy target creature. It can't be regenerated.

Shadow Kin

Flash
At the beginning of your upkeep, each player mills three cards. You may exile a creature card from among the cards milled this way. If you do, Shadow Kin becomes a copy of that card, except it has this ability.

Szadek, Lord of Secrets

Flying
If Szadek, Lord of Secrets would deal combat damage to a player, instead put that many +1/+1 counters on Szadek and that player mills that many cards.

Nemesis of Reason

Whenever Nemesis of Reason attacks, defending player mills ten cards.

Fraying Sanity

Enchant player
At the beginning of each end step, enchanted player mills X cards, where X is the number of cards put into their graveyard from anywhere this turn.

Trepanation Blade

Whenever equipped creature attacks, defending player reveals cards from the top of their library until they reveal a land card. The creature gets +1/+0 until end of turn for each card revealed this way. That player puts the revealed cards into their graveyard.
Equip {2}

Intellect Devourer

Devour Intellect — When Intellect Devourer enters, each opponent exiles a card from their hand until Intellect Devourer leaves the battlefield.
Body Thief — You may play lands and cast spells from among cards exiled with Intellect Devourer. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.

Doom Weaver

Reach
Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Doom Weaver is paired with another creature, each of those creatures has "When this creature dies, draw cards equal to its power."

Squirming Mass

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

Plant Tadpoles

Tap X target creatures. They don't untap during their controllers' next untap steps. (Then exile this card. You may cast the creature later from exile.)

Illithid Harvester

Ceremorphosis — When Illithid Harvester enters, turn any number of target tapped nontoken creatures face down. They're 2/2 Horror creatures.

Illithid Harvester // Plant Tadpoles

Consuming Aberration

Consuming Aberration's power and toughness are each equal to the number of cards in your opponents' graveyards.
Whenever you cast a spell, each opponent reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

Cover of Darkness

As Cover of Darkness enters, choose a creature type.
Creatures of the chosen type have fear. (They can't be blocked except by artifact creatures and/or black creatures.)

King Narfi's Betrayal

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Each player mills four cards. Then you may exile a creature or planeswalker card from each graveyard.
II, III — Until end of turn, you may cast spells from among cards exiled with King Narfi's Betrayal, and you may spend mana as though it were mana of any color to cast those spells.

Nephalia Drownyard

{T}: Add {C}.
{1}{U}{B}, {T}: Target player mills three cards.

Ravenous Chupacabra

When Ravenous Chupacabra enters, destroy target creature an opponent controls.

Necromentia

Choose a card name other than a basic land card name. Search target opponent's graveyard, hand, and library for any number of cards with that name and exile them. That player shuffles, then creates a 2/2 black Zombie creature token for each card exiled from their hand this way.

Carrion Locust

Flying
When Carrion Locust enters, exile target card from an opponent's graveyard. If it was a creature card, that player loses 1 life.

Syr Konrad, the Grim

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad, the Grim deals 1 damage to each opponent.
{1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Duskmantle Guildmage

{1}{U}{B}: Whenever a card is put into an opponent's graveyard from anywhere this turn, that player loses 1 life.
{2}{U}{B}: Target player mills two cards.

Faceless Butcher

When Faceless Butcher enters, exile another target creature.
When Faceless Butcher leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Body Double

You may have Body Double enter as a copy of any creature card in a graveyard.

Nihilith

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Suspend 7—{1}{B} (Rather than cast this card from your hand, you may pay {1}{B} and exile it with seven time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)
Whenever a card is put into an opponent's graveyard from anywhere, if Nihilith is suspended, you may remove a time counter from Nihilith.

Cemetery Illuminator

Flying
Whenever Cemetery Illuminator enters or attacks, exile a card from a graveyard.
You may look at the top card of your library any time.
Once each turn, you may cast a spell from the top of your library if it shares a card type with a card exiled with Cemetery Illuminator.

Getting

Defiler of Flesh

Menace
As an additional cost to cast black permanent spells, you may pay 2 life. Those spells cost {B} less to cast if you paid life this way. This effect reduces only the amount of black mana you pay.
Whenever you cast a black permanent spell, target creature you control gets +1/+1 and gains menace until end of turn.

Siren's Ruse

Exile target creature you control, then return that card to the battlefield under its owner's control. If a Pirate was exiled this way, draw a card.

Elder Brain

Menace
Whenever Elder Brain attacks a player, exile all cards from that player's hand, then they draw that many cards. You may play lands and cast spells from among the exiled cards for as long as they remain exiled. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.

Ravenous Trap

If an opponent had three or more cards put into their graveyard from anywhere this turn, you may pay {0} rather than pay this spell's mana cost.
Exile target player's graveyard.